Crystallography is a scientific discipline that determines the arrangement of atoms in solid, ordered materials. The fundamental approach involves analyzing how waves, such as X-rays, interact with the periodic structure of a crystal lattice. When these waves strike a crystal, they are diffracted according to the spacing of the atomic planes. By measuring these diffraction patterns and applying mathematical principles, it is possible to calculate the precise three-dimensional coordinates and types of atoms composing the material. This method is indispensable across various fields of physical science and biology, providing structural information vital for understanding material properties, designing new functional materials, and elucidating the molecular architecture of macromolecules like proteins.